B-070 Supar: what UACR and GFR don't say…

Abstract Background Soluble urokinase-type plasminogen activator receptor (suPAR) is the circulating form of a three domain membrane protein expressed on a variety of cells, including immunologically active cells, endothelial cells, and podocytes. Diabetic nephropathy (DN) typically manifests with impaired glomerular filtration and microalbuminuria and progresses to end-stage renal disease. The study investigated whether high levels of suPAR may be added to KDIGO models that includes estimated glomerular filtration rate (eGFR) and urine albumin-to-creatinine ratio (UACR) to give more information about diabetic patients at higher risk of DN occurrence. Methods We measured plasma suPAR levels in 142 patients (67F/75M, median age 67 years) admitted to our hospital to check their glucose and glycated A1c hemoglobin (HbA1c) levels. We also recorded information about UACR and eGFR, and the relationship between suPAR levels and these parameters was investigated together with the distribution of suPAR levels according to KDIGO category risk of CKD. Results Among our study population, according to KDIGO risk category, 80 patients were at low risk, 47 were at moderate risk and 13 were at high risk of CKD. Mean plasma suPAR levels are 4.613±3.331 ng/mL, and significant correlation between suPAR and eGFR (P=0.0001) and between suPAR and HbA1c (P=0.0026) were found, while there is not a significant correlation with UACR (p=0.207) . According to KDIGO category risk, suPAR levels significantly increased from low to high risk, in particular, the increase is higher between the first two category (4.176 vs 6.285 ng/mL) risk compared to the highest (7.557 vs 7.427 ng/mL). We classified the 80 patients at low risk for KDIGO according suPAR levels divided into 4 quartiles according to literature (S. Salim Hayek et Al 2015) and 52 of them had suPAR levels in the third and fourth quartiles. Moreover, among these 52 patients, only 5 had HbA1c levels over the therapeutic target of 53 mmol/mol. Conclusions We identified an association between elevated plasma suPAR levels and a decline in the eGFR. However, we did not find a correlation with UACR, this is because suPAR levels are associated with a prospective membrane damage through interference with podocyte migration and apoptosis. According to this analysis, suPAR is a possible best candidate marker to stratify those patients who, according to the KDIGO criteria, are at low risk and have good glycemic compensation, but suPAR levels suggest a more careful follow-up.